For some reason--possibly because Portland is looking pretty good on the map--I've started adding the alleys of Tacoma, WA. I have to say, I thought Eugene, OR had a lot but that was before seeing this town.

For reasons only known to the TIGER folks, it appears that alleys weren't high on their list of things to map, although driveways on country roads were important.

So if you're in the Tacoma area, take a look at the alleys, particularly those that appear to be dead ends and verify whether they are.